This invention was made with Government support under contract N00030-86-C 0083 awarded by the Department of the Navy. The Government has certain rights in this invention.
The present invention relates to a system and method for automatic placement of components on circuit boards and the like and, in particular, to such a system and method for aligning component termini with mating connection pads on such circuit boards.
The placement of components on and attachment to circuit boards and the like requires a registration of the respective mating pads of the component and circuit board. The conventional alignment technique is to mount cameras over the fields of view of interest which comprise both the component leads or pads and the placement pads so that both could be seen simultaneously. Any offsets between the two are noted, and a robot arm holding the component is instructed to orient the component so that its leads are aligned with the circuit board pads, and the two are then placed together and soldered or otherwise attached.
Conventionally, nine or more video cameras with lensing are used to create the overlapping field effect in order to see both sets of pads on the component and the circuit board.
Because of difficulties in developing software for producing a combined image, the alignment of the corresponding pads and, consequently, the placement of the two together is not necessarily accurate. Further, the use of conventional cameras and lensing creates a relatively bulky and costly piece of equipment, which is prone to vibration and consequent error and misalignment. In addition, the illumination required for lighting the component and circuit board pads creates shadowing of the pads and somewhat fuzzy images seen by the cameras, thereby complicating the processing of the images.